Advances in targeting LDL cholesterol: PCSK9 inhibitors and beyond

Chitosan-Based Nanoparticles Targeted Delivery System: In Treatment Approach for Dyslipidemia

Hyperlipidemia, characterized by abnormally high lipid levels in the bloodstream, is a significant risk factor for cardiovascular diseases. Conventional treatments have limitations in efficacy and may lead to side effects. Nanotechnology offers unique advantages in drug delivery, including improved drug stability, prolonged circulation time, and enhanced tissue targeting. Using nanoparticles as carriers, therapeutic agents can be precisely delivered to the target site, such as the liver or arterial walls, where lipid metabolism occurs. Chitosan nanoparticles represent an advanced approach engineered with precision to target atherosclerotic plaques. They have dual functionalities, serving therapeutic and diagnostic purposes in managing atherosclerosis. Targeting strategies involve coating nanoparticles with ligands or antibodies that recognize specific receptors overexpressed in hyperlipidemic conditions. This selective uptake maximizes the therapeutic effect while minimizing off-target effects, making it a promising alternative to traditional treatments. The review provides an overview of recent research developments for managing dyslipidemia based on the molecular target pathway of dyslipidemia, focusing on Chitosan-based delivery systems that allow controlled drug release, targeting, and enhancing patient compliance.

Angiopoietin-Like 3 Antibody Therapy in Patients With Suboptimally Controlled Hyperlipidemia: A Phase 2 Study

BACKGROUND

Angiopoietin-like 3 (ANGPTL-3) inhibits the activity of lipoprotein lipase and endothelial lipase, increasing both serum low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels. SHR-1918 is a fully human monoclonal antibody against ANGPTL-3.

OBJECTIVES

The aim of this study was to assess the lipid-altering efficacy and safety of SHR-1918 in patients at moderate or higher risk of atherosclerotic cardiovascular disease (ASCVD) with suboptimally controlled hyperlipidemia.

METHODS

A multicenter, randomized, double-blind, placebo-controlled, dose-escalation phase 2 study was designed to evaluate the effects of SHR-1918 in hypercholesterolemic patients, who did not achieve optimal LDL-C after 4 to 8 weeks of standard lipid-lowering therapies. A total of 333 patients were enrolled sequentially into 1 of 8 dose cohorts at a 4:1 (active/placebo) ratio. Patients received subcutaneous SHR-1918 at doses of 150, 300, or 600 mg every 4 weeks (Q4W), or SHR-1918 at a dose of 600 mg every 8 weeks (Q8W), alternating with placebo for a total treatment period of 16 weeks. The extension treatment included subcutaneous SHR-1918 at a dose of 150, 300, or 600 mg Q4W over 36 weeks, or SHR-1918 a dose of 600 mg Q8W over 40 weeks and then followed for safety. Prespecified endpoints included percentage change from baseline in LDL-C and TG. Safety was assessed with laboratory test results and by the incidence and severity of adverse events.

RESULTS

SHR-1918 demonstrated a clear dose-response relationship with respect to percentage LDL-C lowering for both Q4W and Q8W administration: 21.7%, 27.3%, and 29.9% with 150, 300, and 600 mg Q4W compared with placebo, respectively, and 22.5% with 600 mg Q8W compared with placebo. SHR-1918 also substantially reduced TG, non-high-density lipoprotein cholesterol, apolipoprotein B, and apolipoprotein A1, with a better achievement of LDL-C targets. SHR-1918 was generally well-tolerated.

CONCLUSIONS

Based on standard lipid-lowering therapy, ANGPTL-3 inhibition with SHR-1918 further reduces LDL-C by 21.7% to 29.9% in patients at moderate or higher risk of ASCVD. These additional reductions are both dose and dosing frequency dependent. (Evaluate the Efficacy and Safety of SHR-1918 in Patients With Hyperlipidemic; NCT06109831).

PCSK9 Regulates Cardiac Mitochondrial Cholesterol by Promoting TSPO Degradation

BACKGROUND

Cholesterol is critical for mitochondrial membrane structure and function. Given the emergence of mitochondria as a key factor in the pathogenesis of heart failure, mitochondrial cholesterol homeostasis may be crucial for maintaining mitochondrial properties and thus cardiac function. We previously showed that CM-Pcsk9-/- mice (mice with cardiomyocyte-specific deletion of the gene encoding PCSK9 [proprotein convertase subtilisin-kexin type 9]) have impaired cardiomyocyte mitochondrial bioenergetics and heart function, paralleled by cardiomyocyte mitochondrial cholesterol accumulation and an increased number of mitochondria-endoplasmic reticulum contacts. However, the mechanisms linking PCSK9 to mitochondrial cholesterol homeostasis remain unclear. We hypothesized that PCSK9 acts on proteins involved in mitochondrial cholesterol trafficking in the heart to maintain cardiac mitochondrial function.

METHODS

By performing RNA sequencing and immunoblot on hearts from CM-Pcsk9-/- and CM-Pcsk9+/+ (without cardiomyocyte-specific deletion of Pcsk9) mice, we showed that TSPO (translocator protein) was increased by Pcsk9 deficiency. To investigate the relationship between TSPO levels and heart function in humans, we compared the transcriptome of human left ventricles with high versus low TSPO levels. We used H9c2 (a rat cardiomyoblast cell line) cardiomyocytes to explore the mechanism linking PCSK9/TSPO to mitochondrial cholesterol content and function. The impact of reduced TSPO levels on cardiac function and mitochondrial oxidation in CM-Pcsk9-/- mice was tested using adeno-associated virus serotype 9 short hairpin TSPO.

RESULTS

Both gene and protein levels of TSPO, a mitochondrial protein involved in cholesterol transport, were increased in CM-Pcsk9-/- mouse hearts. Transcriptome analysis showed that high TSPO expression in human left ventricles was associated with impaired mitochondrial and cardiac function. We showed that PCSK9 induced TSPO degradation through a proteasomal mechanism that occurs in cardiomyocytes but not hepatocytes and contributes to maintaining normal mitochondrial cholesterol composition and function. At the molecular level, endoplasmic reticulum-resident PCSK9 interacted with GRP78 (glucose regulatory protein 78) , reducing GRP78-TSPO interactions and leading to TSPO misfolding and degradation by the ubiquitin-proteasome pathway. Importantly, gene therapy-induced downregulation of TSPO in CM-Pcsk9-/- mice prevented mitochondrial cholesterol accumulation and improved cardiac function.

CONCLUSIONS

These findings indicate that PCSK9 regulates mitochondrial cholesterol levels by modulating the TSPO degradation in the heart. Modulation of mitochondrial cholesterol by targeting TSPO may be a promising therapeutic approach for heart failure.

PCSK9 in Vascular Aging and Age-Related Diseases

The aging process significantly contributes to human disease, and as worldwide life expectancy increases, addressing the challenges of aging and age-related cardiovascular diseases is becoming increasingly urgent. Vascular aging is a key link between aging and the development of age-related diseases. Recent studies indicate that proprotein convertase subtilisin/kexin type 9 (PCSK9), a type of protein involved in the metabolism of lipids, is crucial in modulating vascular aging by affecting the physiological functioning of vascular cells. PCSK9 is linked to lipid metabolism and chronic inflammation and is involved in regulating senescence-related activities, including migration, proliferation, apoptosis, and differentiation. These factors contribute to the aging of vascular cells and age-related vascular diseases, including atherosclerosis, hypertension, coronary artery disease, and cerebrovascular diseases. Given its involvement in these processes, this article provides a comprehensive summary of PCSK9's regulatory functions in vascular aging, highlighting potential therapeutic targets for combating age-related cardiovascular diseases.

Inadequate Response to PCSK9 Inhibitors

BACKGROUND

Suboptimal response to various proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) therapies has been reported in the literature; however, inadequate response to proprotein convertase subtilisin/kexin type 9 monoclonal antibodies and small interference RNA is rare to our knowledge.

CASE SUMMARY

A 68-year-old woman with hypercholesterolemia (baseline low-density lipoprotein cholesterol [LDL-C]: 205 mg/dL), subclinical atherosclerosis (coronary artery calcium: 204 Agatston units), and elevated lipoprotein(a) (217 nmol/L) experienced debilitating muscle aches and other limiting side effects with statins, ezetimibe, and bempedoic acid, leading to the discontinuation of all oral LDL-C lowering agents. Alirocumab reduced LDL-C to 162 mg/dL after 6 doses. Inclisiran resulted in LDL-C levels of 165 and 199 mg/dL after the first and second doses, respectively. Evolocumab plateaued LDL-C to 155 mg/dL after 7 doses. All the PCSK9i therapies were <25% LDL-C lowering.

DISCUSSION

The patient's response to multiple forms of PCSK9i was less than expected. Real-world data show a higher rate of suboptimal proprotein convertase subtilisin/kexin type 9 responses than reported in randomized clinical trials (7.5% vs 1%), warranting further research.

TAKE-HOME MESSAGES

A higher rate of suboptimal PCSK9i responses have been reported in real-world data than in randomized clinical trials (7.5% vs 1%), warranting further investigation to understand mechanisms. The use of combination therapy based on individual response and tolerance is essential to assure goal attainment and improve residual risk in patients with suboptimal response.

Combined action of dietary-based approaches and therapeutic agents on cholesterol metabolism and main related diseases

BACKGROUND

Dyslipidaemia is among the major causes of severe diseases and, despite being well-established, the hypocholesterolaemic therapies still face significant concerns about potential side effects (such as myopathy, myalgia, liver injury digestive problems, or mental fuzziness in some people taking statins), interaction with other drugs or specific foods. Accordingly, this review describes the latest developments in the most effective therapies to control and regulate dyslipidaemia.

SCOPE AND APPROACH

Herein, the metabolic dynamics of cholesterol and their integration with the current therapies: statins, bile acid sequestrants, fibrates, niacin, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, reconstituted high-density lipoprotein (rHDL), or anti-inflammatory and immune-modulating therapies), were compared focusing their effectiveness, patients' adhesion and typical side-effects. Likewise, the interaction of these therapies with recommended dietary habits, focusing functional foods and nutraceuticals uptake were also considered.

KEY FINDINGS AND CONCLUSIONS

Since none of the current therapeutic alternatives represent an ideal solution (mainly due to side-effects or patients' tolerance), the potential adjuvant action of selected diets (and other healthy habits) was proposed as a way to improve the cholesterol-lowering effectiveness, while reducing the adverse effects caused by dose-increase or continuous uptake of alternating therapeutic agents. In general, the relevance of well-adapted diets must be acknowledged and their potential effects must be exhorted among patients, who need to be aware of the associated multifactorial advantages.

Refining the impact of early intermittent hyperlipidemia on atherosclerosis: Unveiling the role of neutrophil reprogramming, sex differences, gut microbiota, and maternal hypercholesterolemia

Atherosclerotic cardiovascular diseases (ASCVDs) remain a leading cause of mortality, with early cholesterol control being pivotal in mitigating long-term risk. Recent findings suggest that intermittent hyperlipidemia, characterized by oscillatory cholesterol exposure, uniquely accelerates atherosclerosis compared to continuous high-fat diets. This review synthesizes emerging evidence on early intermittent hyperlipidemia's impact on atherogenesis, emphasizing macrophage dysfunction, autophagy impairment, and efferocytosis deficits. We also discuss critical gaps, including sex-specific differences, gut-microbiota interactions, and the influence of maternal hypercholesterolemia. Notably, recent insights into IL-1β-dependent neutrophil reprogramming under oscillatory diets reveal novel inflammatory mechanisms driving plaque destabilization. Addressing these gaps will advance our understanding of early atherogenesis and guide the development of innovative prevention strategies and therapeutic interventions.

Gene Therapy: Towards a New Era of Medicine

Over the past years, many significant advances have been made in the field of gene therapy and shown promising results in clinical trials conducted. Gene therapy aims at modifying or replacing a defective, inefficient, or nonfunctional gene with a healthy, functional gene by administration of genome material into the cell to cure genetic diseases. Various methods have been devised to do this by using several viral and non-viral vectors which are either administered by in vivo or ex vivo technique. Viral vectors are best suitable for this therapy due to their potential to invade cells and deliver their genetic material whereas non-viral vectors are less efficient than viral vectors but possess some advantages such as less immunogenic response and large gene carrying capacity. Recent advances in biotechnology such as CRISPR-Cas9 mediated genome engineering and Cancer treatment with Chimeric antigen receptor (CAR) T-cell therapy are addressed in this review. This review article also delves into some recent research studies, gene therapy trials, and its applications, laying out future hopes for gene therapy in the treatment of various diseases namely haemophilia, Muscular dystrophy, SCID, Sickle cell disease, Familial Hypercholesterolemia, Cystic Fibrosis. Additionally, it also includes various nanoformulations and clinical trial data related to gene therapy.

Immune-Mediated Inflammatory Diseases, Dyslipidemia, and Cardiovascular Risk: A Complex Interplay

Individuals with autoimmune inflammatory diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and psoriasis, are at increased risk for cardiovascular disease. While these diseases share common features of systemic inflammation, the impact of individual autoimmune inflammatory conditions on circulating lipids and lipoproteins varies by specific disease, disease activity, and the immune-suppressing medications used to treat these conditions. A common feature observed in many autoimmune inflammatory diseases is the development of a proatherogenic dyslipidemic state, characterized by dysfunctional HDLs (high-density lipoproteins) and increased oxidation of LDLs (low-density lipoproteins). Various disease-modifying antirheumatic drugs also have complex and variable effects on lipids, and it is critical to take this into consideration when evaluating lipid-related risk in individuals with immune-mediated inflammatory conditions. This review aims to critically evaluate the current understanding of the relationship between immune-mediated inflammatory diseases and dyslipidemia, the underlying mechanisms contributing to atherogenesis, and the impact of various pharmacotherapies on lipid profiles and cardiovascular risk. We also discuss the role of lipid-lowering therapies, particularly statins, in managing residual risk in this high-risk population and explore the potential of emerging therapies with complementary anti-inflammatory and lipid-lowering effects.

PCSK9 Inhibitors: Focus on Evolocumab and Its Impact on Atherosclerosis Progression

This paper investigates the therapeutic use of PCSK9 inhibitors, particularly Evolocumab, as monoclonal antibodies for the treatment of atherosclerosis based on recent literature reviews. PCSK9 is an outstanding example of a breakthrough in medical science, with advancements in understanding its biological function driving substantial progress in atherosclerosis treatment. Atherosclerotic cardiovascular disease (ASCVD) is a leading global cause of mortality, imposing substantial financial burdens on healthcare systems. Elevated low-density lipoprotein cholesterol (LDL-C), a modifiable risk factor, plays a pivotal role in the development of ASCVD. Emerging treatments such as PCSK9 inhibitors are now being introduced to combat this issue, with the goal of reducing ASCVD risk by directly targeting LDL-C levels. This discovery highlighted the potential of monoclonal antibodies to inhibit PCSK9, thereby enhancing LDL-C receptor activity. This breakthrough led to the development of Alirocumab and Evolocumab inhibitors, which typically reduce LDL-C levels by approximately 50%. This research underscores the importance of PCSK9 inhibitors in treating ASCVD, drawing on evidence from various randomized controlled trials such as FOURIER, ODYSSEY OUTCOMES, and VESALIUS-CV. These trials have also shown that PCSK9 inhibitors are effective and safe for the treatment of several cardiovascular disorders. PCSK9 inhibitors are therefore useful in patients who do not reach their target LDL-C levels when on the highest doses of statins or patients with very high cardiovascular risk who cannot tolerate statins at all.

Life-Threatening Reaction to Lifesaving Medication: Stepwise Approach to Severe Adverse Reactions to PCSK-9 Monoclonal Antibodies

Typical side effects of proprotein convertase subtilisin/kexin type 9 monoclonal antibodies including influenza-like illness and injection site reactions, are minor and well tolerated. This case, however, highlights a less common but severe reaction, indicating the need for clinicians to understand and manage potential rare side effects noted with biologics.